Waisman Center investigators study Intellectual and Developmental Disabilities (IDD) through elucidation of molecular pathways that are altered in genetic and epigenetic conditions affecting nervous system function. Compared with other genetically tractable model organisms, rodents afford the highest similarity to humans in anatomy, physiology, and genetics. Thus, study of IDD has relied on development of rodent models of various disorders. In recent years, complementary development of human stem cell-based models to study similar processes has greatly expanded the scope and relevance of studies of IDD. Investigators of the Waisman Center have spearheaded research in a number of IDD conditions, and many investigators rely on complementary mouse and human stem cell models to study different facets of these disorders. Use of these models provides the means to evaluate candidate therapeutics, as well as develop novel screens to identify promising compounds. The resources of the IDD Models Core, almost all housed within the Waisman Center itself, provide the tools for development of mouse and human stem-cell derived models of IDD. Therefore, we propose two specific aims for the next project period. Aim 1 is to create and analyze rodent models of IDD. The objectives of this aim are to: 1) provide advanced technical services in the generation, cryopreservation, and maintenance of mutant or genetically engineered strains of mice and rats; 2) provide advanced behavioral testing services and facilities for the phenotypic characterization of novel strains of rodents; 3) provide training and consultation to investigators and laboratory personnel; and 4) facilitate maintenance and exchange of unique rodent models between institutions. Aim 2 is to to develop human stem cell models of IDD and facilitate phenotyping of neurodevelopmental defects. The objectives of this aim are to: (1) support the generation of induced pluripotent stem cell (iPSC) lines directly from individuals diagnosed with IDD; (2) support development of IDD-specific PSC lines through genome editing; (3) provide high quality, cost effective, cellular and molecular neuroscience technology and expertise to IDDRC investigators to facilitate phenotyping of neurodevelopmental defects in human PSC derived cells and (4) provide training and technical support in human stem cell culture, phenotyping and gene editing to promote usage of new approaches by our investigators. These initiatives are further served by state-of-the-art imaging and molecular biology analysis tools housed within the Waisman Center. With support from the Administrative Core, linkages are provided to complementary capabilities elsewhere on campus, such as those offered by the UW Biotechnology Center, UW Comprehensive Cancer Center, and other partnerships. These resources and partnerships are leveraged to facilitate usage of a large repertoire of techniques to enhance multidimensional analysis of IDD models, and to promote the development and testing of potential therapeutics.